HONOLULU, March 23 - The melting snow of the Sierra Nevada fell away from the airman inch by inch. He lay facedown, his hair thick and blond atop a crushed head.

Last October, two hikers on the Darwin Glacier in California spotted a piece of cloth, moved closer and found him. His arms were spread as if in free fall. The parachute pack on his back read "U.S. Army," and it was unopened.

The frozen airman found last year by hikers on Darwin Glacier in Kings Canyon National Park in California.

A military team arrived to cut him out, ice and all, and transported him to a remote laboratory at Hickam Air Force Base on Oahu, where anthropologists gently thawed him by spraying him with water.

A mummified human time capsule took its broken shape before them. He carried a Sheaffer fountain pen. The newest coin in his pocket was dated 1942. But his nameplate was terribly corroded, and so the case of the frozen airman took its place among thousands of unidentified remains boxed on crowded shelves or spread on metal tables here at the Joint P.O.W./M.I.A. Accounting Command.

On Friday, the World War II airman will be laid to rest in a private ceremony in his hometown, Brainerd, Minn., after teams of anthropologists and historians here pieced together his identity as the missing crew member from a plane crash 63 years ago. His journey from the snow to the laboratory to the grave fulfills what a commander here describes as the military's "most sacred of promises" to its members.

"We're going back to that basic promise we make to youngsters who enter the military," said Col. Claude H. Davis III of the Marines, deputy commander of the joint command, which is dedicated to finding and identifying the remains of Americans from all wars. "We're going to make sure they get home again."

An estimated 88,000 military personnel remain unaccounted for, a vast majority, 78,000, from World War II, and most of those are believed to be lost at sea.

About 8,100 service members remain missing from the Korean War; from Vietnam, 1,807. There are 126 military or intelligence officers missing from the cold war, mostly in spy planes that crashed. Some of the missing are civilians like Red Cross workers and C.I.A. agents, and some, like the frozen airman, went missing here in the United States.

The work is slow going. The 425-member staff of the accounting command identifies an average of six people a month, about 75 a year, each one ending with a flag-draped return to a family, often distant relatives.

"It's not like you're just working on a bunch of bones," Johnie E. Webb, 60, the senior adviser, said. "It's very rewarding. It's also very agonizing. Family members are getting older."

The laboratory is part cutting edge, part time warp. A computer can superimpose the image of an unidentified skull over a man's smiling picture, a haunting montage of optimism and fate, to see whether the eye sockets and teeth match up.

A bone sample the size of a thumb can yield mitochondrial DNA to link a man missing 60 years to a child in short pants.

Books about old military buttons and medals and knives line the walls. Broken stopwatches mark the time of long-ago crashes.

The command operates on an annual budget of $45 million to $50 million. The front end of the process, finding the remains, is expensive and often time consuming, involving linguists, investigators and hours spent developing leads and studying flight plans or battle reports.

Eighteen recovery teams of up to 14 members make several 35-day missions a year to Southeast Asia, Korea, Europe and the Pacific theater of World War II.

The easy cases are already closed.

"All the apples pretty close to the tree are gone," said Robert Richeson, deputy director of the section that oversees investigations. "The crash sites we get to these days are a little tougher to do."

In "isolated grave" cases, where an individual has been buried or left on a battlefield, the rate of recovery and identification is 17 percent of all sites investigated, Mr. Richeson said.

A stroll through the vault of remains shows where extractions were successful: Belgium, Burma, Cambodia, France, Laos, Papua and North and South Korea.

None of the remains in the boxes have been identified, and the frustration of the families of the dead runs deep. An old letter in a file from the mother of a missing Korean War soldier reads: "I guess the search party didn't do a good job. I wish I was there. I would of dug every inch of that ground myself."

Most crash-site investigations begin just as the airman's did, with someone happening upon it. After the hikers' discovery on Oct. 15, which generated widespread interest and news coverage, historians with the command turned to accident reports from the 1940's, in hopes of finding a match in the Sierra Nevada.

There it was. On the morning of Nov. 18, 1942, three young aviation cadets and a pilot took off from Mather Field, near Sacramento, for a four-hour navigational training flight. The airplane carried five hours' worth of fuel and never returned. The searchers - military crews, police officers, loggers and local residents - found nothing.

Almost five years later, two college students found parts of the airplane, a nametag belonging to one of the men and what a search team's report described as "a small piece of frozen flesh." The remains were interred in a group burial in San Bruno, Calif., that bore the names of all four men.

If the frozen airman was one of the men, which one? His features were long ago obliterated by the elements.

"Even examining his body there on the autopsy table," Robert Mann, deputy scientific director at the command, said, "it was difficult to tell what we were looking at."

One leg was gone. There was no face, only deep holes in a dark mass. He had lost six teeth while alive, their sockets long ago healed, and one tooth at his death. The blond hair fell to the right, in the style of the day.

Most recoveries involve, at best, skeletons, the dirt around them slowly cleared with trowels and brushes. But more often there are just jagged pieces of bone no larger than a bullet, and even those are hard won.
"Every one's a new challenge," said Gregory Fox, 54, an archaeologist who works on several recovery missions a year. "You're on a 60-foot slope this time or a cliff or you're diverting a stream."

Often, they find nothing.

"I went on two missions without finding anything," Capt. Loren Graham, 34, a recovery team leader, said. "That's 60 days. We found buckets and buckets, but we didn't find any bone and we didn't find any teeth."
In Southeast Asia, many crash sites were long ago picked over by looters. Some cases begin when a son or daughter in Vietnam or Laos finds American dog tags among a dead parent's possessions and takes them to the authorities.

On April 7, 2001, a command helicopter carrying a team searching for remains crashed in Quang Binh Province in Vietnam, killing all seven Americans and nine Vietnamese on board. A memorial stands outside the command office near Pearl Harbor.

Digging out the airman in the Sierra was relatively easy. At the laboratory, scientists picked through his modest personal effects - a broken comb, the pen, six pennies, one nickel, four dimes, three address books that were illegible.

Most unusual was a scrap of paper that they fed into a high-resolution video spectral comparator, discovering what appears to be a bawdy limerick that read in part, "A bird in the hand is worth two in the bush, this the girls all know." The parachute on his back was intact. Spread on the asphalt outside, it even looked usable.

Finally, the corroded nameplate. Anthropologists used different sources of light to photograph the plate until teasing four letters from the scarred metal: "EO A. M."

One of the dead men was listed as Leo M. Mustonen, age 22. Close to the nameplate, but with a different middle initial. His death report listed his emergency contacts as his parents, Arvid and Anna Mustonen, Finnish immigrants on Maple Street in Brainerd, Minn.

A piece of bone generated mitochondrial DNA, but for a successful match, a sample has to be drawn from a maternal relative. The lone relatives of the airman named Mustonen were the wife and daughters of his brother, in Jacksonville, Fla. Their DNA would not be of help.

But relatives of the other three missing airmen - John Mortenson, 25, of Idaho; Ernest Munn, 23, of Ohio; and the pilot, Second Lt. William Gamber, 23, also of Ohio - were found. None matched the frozen airman's DNA.

Finally, anthropologists found that Mustonen's name had been misspelled on his nameplate all along. The A should have been M.

So by the nametag and genetic default, and "to the exclusion of other reasonable possibilities," the airman was identified as Leo M. Mustonen. Formal notification was made to Leane Mustonen Ross in Jacksonville, who was not born when the airplane carrying her father's brother crashed.

His remains were cremated and shipped to Minnesota.

Ms. Ross said imagining her uncle's final moments haunted her.

"He actually made it out of the plane," she said. "Then, the parachute didn't open. He might not have had enough altitude to open his parachute."

She said she knew of three people alive who had known her uncle, and she planned the funeral for Friday at the First Lutheran Church in Brainerd. A military team will perform taps and fire a 21-gun salute.

A picture of the mummified airman is in Ms. Ross's house, in a report from the command, but she said she would not look. She prefers the high school picture of her uncle when he was 18, a member of a school band, his young face stern, his blond hair swept to the right.

A forensic anthropologist, Hugh Tuller, at Joint P.O.W./M.I.A. Accounting Command in Honolulu. The laboratory identifies 75 people a year, each ending with a flag-draped return to a family, often distant relatives.